Viscous hydrocarbon recovery is a segment of the overall hydrocarbon recovery industry that is increasingly important from the standpoint of global hydrocarbon reserves and associated product cost. In view hereof, there is increasing pressure to develop new technologies capable of producing viscous reserves economically and efficiently. Steam Assisted Gravity Drainage (SAGD) is one technology that is being used and explored with good results in some wellbore systems. Other wellbore systems however where there is a significant horizontal or near horizontal length of the wellbore system present profile challenges both for heat distribution and for production. In some cases, similar issues arise even in vertical systems.
Both inflow and outflow profiles (e.g. production and stimulation) are desired to be as uniform as possible relative to the particular borehole. This should enhance efficiency as well as avoid early water breakthrough. Breakthrough is clearly inefficient as hydrocarbon material is likely to be left in situ rather than being produced. Profiles are important in all well types but it will be understood that the more viscous the target material the greater the difficulty in maintaining a uniform profile.
Another issue in conjunction with SAGD systems is that the heat of steam injected to facilitate hydrocarbon recovery is sufficient to damage downhole components due to thermal expansion of the components. This can increase expenses to operators and reduce recovery of target fluids. Since viscous hydrocarbon reserves are likely to become only more important as other resources become depleted, configurations and methods that improve recovery of viscous hydrocarbons from earth formations will continue to be well received by the art.